I fixed the links above, but I'm going to need to do a new set. After looking at your plumbing, and hearing your description of the pump motor temp, I'm think you need a more complete rebuild.

If you replace your piping, and replace your motor with a 1HP 2 speed, you'll filter better, and save a LOT of money. Your existing motor is likely approaching failure, as hot as it's been running.

Pentair 355003S 1 HP 2 spd Square Flange Motor for SuperFlo Pump
Pentair 355067 1 HP impeller
Pentair 355617 1 HP diffuser

When you buy, do so by part # (355003S, 355067, 355617) -- the parts are confusing, and overlap different models in odd ways. You can should confirm using the Pentair Superflo manual, pg 12, before buying.

The seal kit is the same as above.

When you re-install, use MIP / FIP combined couplings, with blue dope:
2" MIP
2" FIP
Blue dope
Use those pairs every where you cut pipe, so NEXT time, you can repair by simply unscrewing 1/2 of the pair! If you prefer, you can use unions, instead:
2" PVC Union